Sir Alex Ferguson has expressed his irritation about the way "people jumping on the bandwagon" had brought Manchester United's policy of signing young players under scrutiny and questioned whether it was based on jealousy because of the club's success at unearthing outstanding talent. "We are good at it and, obviously, it rankles with a lot of people," the United manager said.

The president of Le Havre, Jean-Pierre Louvel, accused United this week of offering a house and £170,000 to the parents of a 16-year-old player, Paul Pogba, to persuade him to move to England. United have threatened Louvel with legal action and Ferguson said: "This was an accusation aimed at us by some frustrated director, and he is now going to have to retract it."

Chelsea have been banned from the next two transfer windows for inducing a teenager to break his contract with Lens and United's dealings have also caused consternation at Fiorentina, who have written to Fifa about the Premier League champions' signing of a 16-year-old Italian defender, Michele Fornasier.

"They [other clubs] are always going to bring Manchester United into it because we are the biggest club, but they do it without any foundation, or knowledge about the situation whatsoever," Ferguson said. "There are a lot of people jumping on the bandwagon, but I can assure you that Manchester United behave absolutely correctly in all their dealings with young players and their parents.

"There has never ever been a case of us paying parents. It would be crazy to contemplate that because it would be the biggest headache you could ever have. We behave impeccably – what other clubs do is obviously subject to a lot of controversy and speculation, but I'm confident about our own club."

As for the moral issue of taking a young boy from abroad, Federico Macheda being one example after moving to England from Rome at the age of 16, Ferguson said: "The EU allows players to move. That's a fact. You can't stop a boy, once he has left school, moving from his country. So, that's not an issue. We are well within the regulations."

A lot of the problems, according to Ferguson, originate from the Football Association's 90-minute rule, which limits the choice of young English players depending on where they live.

"There is a weakness in the academy system as far as Manchester United are concerned. We can't scout a boy on the south coast of England, or the north-east, or anywhere in the east of England. Yet we can bring in a boy from Brazil. It seems ludicrous. We have said from the day the system started there is no doubt there is a weakness in that respect.

"We would never have got David Beckham under the present situation and you have to ask what would a boy's best chance be of getting to the top. Would it be at Torquay, or somewhere like that, or at big clubs like Arsenal, Manchester United, Chelsea, all the big clubs, historically?"

Ferguson revealed that Rio Ferdinand was in contention for United's match at Tottenham Hotspur on Saturday, but John O'Shea will be missing after suffering a calf injury on duty with the Republic of Ireland. "Rio has been in training this week and has a got a chance for Saturday; I'm not sure how big a chance but he has got a chance."